Floor switch



Feb. 21, 1928.

H. W. CRANE FLOOR SWITCH Filed Dec. 27. 1920 Patented Feb. 21, 1928.

HERBERT W. CRANE, OF CHICAGO, ILLINOIS.

FLOOR SWITCH.

Application filed December 27, 1920. Serial No. 433,172.

My invention relates to electric switches and particularly to a novel floor or pavement switch adapted for use in actuating door opening or closing motors.

It has been found to be desirable if not essential in handling closures, particularly large or heavy closures such as are employed on garages, treighthouses, etc., to employ power means for effecting the opening and closing movements. I have devised effective means for accomplishing this result, such means being shown in my prior Patent No. 1,290,718, dated January 7, 1919. lVhen mechanism of this character is employed on doors of certain kinds it is desirable to provide means operable by the weight of a vehicle, such as an automobile, for closing a circuit and energizing the motor. However, much diiiiculty has been experienced due to the fact that such a switch is in most cases exposed to the weather and to loads imposed by vehicles of widely different weights. I have, however, devised means whereby a. circuit may be closed by means of a pavement switch, the parts being entirely enclosed within a water-tight housing. To that end lemploy a casing or housing adapted to be sunk into the pavement or floor with its upper surface flush with the floor. The top wall of the housing is in the form of a flexible plate, the motion being transmitted to the switch by flexing said plate. However, realizing the likelihood of breakage of the plate, due to repeated flexure, I have so arranged the parts that the motion of the plate is greatly multiplied by means of suitable levers. Thus the required movement of the switch, which need be but slight as for instance, 4 of an inch may be effected by movement of the plate of less than 1/1000 of an inch. By this means also I am enabled to so resist the movement of the parts by a spring located adjacent to the switch that the floor switch cannot be operated by the weight of a person and the switch may readily be located in a common passageway for such persons.

The invention will be more readily understood with reference to the accompanying drawings, in which,

Fig. 1 is a longitudinal sectional view through a device constructed in accordance with my invention; and

Fig. 2 is a plan view of the same with the plate broken away to show the relation of the bearings and levers.

In the drawings it will be seen that I provide a casing or housing 10 having an open top adapted to be closed by a plate 11, which is securely riveted thereto. A suitable gasket or packing means will be employed whereby to assure the exclusion of moisture from the casing. At one end the housing will be provided with a coupling 12 to which a pipe or conduit for electric wires may be attached. At the same end and on top of the casing I provide a threaded opening 13 by means of which access may be had to the casing without interfering with the plate. This opening may be closed by a plug, not shown.

Mounted beneath the plate 11 is a beam or bar 14; adapted for limited vertical movement in response to the flexing of the plate by imposing a weight thereon. Located beneath the beam 14: are levers 15, which at their outer ends have a bearing on rollers 16, resting on the frame and support the beam 1% by means of rollers 17, located near the ends of the beam and also near the outer ends of the levers. Thus the movement of the beam is transmited to the levers 15 and multiplied to the extent of the distance separating the rollers 16, 17, from each other. At their inner ends the levers 15 rest upon a roller 18 which in turn rests upon the rear end of a two-part lever 19. The latter lever has a bearing on the housing through a roller 20 at a point close to the roller 18; thus the motion of the plate is again multiplied. The two-piece lever 19 carries at its outer extremity an insulating block 21, which atfords means for mounting a contact piece 22 thereon. A wire 23 communicates with this contact piece and another wire 2 1 communicates with the contact piece 25, said wires being admitted through the conduit not shown and heretofore referred to. A bolt 26 is secured in the housing and a spring 27 carried by the bolt bears against the outer end of the lever 19 and tends to force the contact pieces out of engagement. The compression of the spring may be adjusted by means of a nut 28 carried by the bolt.

It will be seen that by employing the mechanism shown the motion of the flexible plate may be greatly multiplied and the plate is not likely to become broken even after long use. It vvill be seen also that Wherever a forceis applied to the plate it Will be communicated to the levers With the same degree mounted in the housing, roller bearings posiof intensity.

Obviously the invention is capable of much modification and I do not Wish to be limited except as indicated in the appended claim.

I claim:

A switch of the character described includ ing a housing having an open top, a switch tioned in the housing and supporting a series of motion multiplying levers for operating the switch, roller bearings carried by the motfon multiplying levers, an inflexible bar carried by the last mentioned roller bearings and adapted for vertical movement in the housing, and asubstantially rigid though flexible plate received overthe top of the housing and forming a closure for the open top thereof, said plate adapted to be flexed a predetermined and relatively heavy load to depress the inflexible bar to in turn impartmovement to the motion multiplying levers to operate the switch.

Signed at Chicago, Illinois, this23rd day of December, 1920. V HERBERT W. CRANE. 

